JPH0679331A - Lubrication method in hot rolling - Google Patents

Abstract

(57) [Summary] [Purpose] To improve lubricity in hot rolling. Facilitates the supply of lubricant. [Structure] On the entry side of a hot rolling mill, a lubricant is applied to the surface of the material 1 by spraying or the like. The lubricant is graphite,
One or two kinds of mica: 10 to 60% by weight, anhydrous sodium silicate: 10 to 50% by weight, and a viscosity of 200
It is a liquid adjusted to ~ 5000 cp. Excess lubricant accumulated on the material 1 is removed by air. Even if the lubricant is excessively supplied, the indentation does not occur and the lubricant can be excessively supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubrication method in hot rolling, which is suitable for hot die rolling and the like used for manufacturing deformed materials such as shape steel and sheet pile.

[0002]

2. Description of the Related Art H-shaped steel, which is a typical profile material, is produced by feeding a heated material to a hot rolling mill and gradually processing the material into a product shape with a plurality of rolling rolls of the hot rolling mill. Manufactured by going. The hot rolling of this H-section steel is
It is roughly divided into hole rolling and universal rolling. As shown in FIG. 1 (A), the hole rolling uses a pair of upper and lower hole rolls 2 and 3 which are fitted to each other for processing the material 1, and the universal rolling shows in FIG. 1 (B). Thus, the material 1 is processed using the pair of left and right vertical rolls 4 and 4 and the pair of upper and lower horizontal rolls 5 and 5. The material 1 passes through the rolling mill with the web 1b sandwiched between the flanges 1a and 1a being horizontal.

In any rolling, the material 1 is subjected to severe processing, and in the case of the caliber rolling, the deformation of the upper surface of the web 1b which comes into contact with the convex portion of the upper caliber roll 2 is large, and this portion is extremely high. The surface pressure is likely to cause seizure flaws. Also,
In universal rolling, each end face of horizontal rolls 5 and 5,
Severe sliding friction occurs between the inner surface of the flange 1b that is in contact therewith, and seizure easily occurs. Therefore, the contact portion between the material 1 and the rolling roll needs to be sufficiently lubricated.

Conventionally, this lubrication has been carried out mainly by the following four methods. The first is a method of directly injecting oil onto a rolling roll. The second is a method of directly injecting a mixed liquid of oil and water or emuljun to a rolling roll. The third is a method in which a felt containing oil is pressed against a rolling roll to supply oil. The fourth is a method in which powder graphite solidified into a predetermined shape is pressed against a rolling roll and coated.

[0005]

[Problems to be Solved by the Invention]
In the case of lubrication using oil No. 3, since oil mixes with the cooling water for cooling the rolling rolls, a large-scale oil recovery device is required, which causes a problem of increased equipment cost. Further, there is a problem that the smoke odor of oil and the contamination around the rolling mill are unavoidable, which deteriorates the working environment. Further, the water film of the roll cooling water weakens the adhesive force of the oil, and the cooling water makes it easier for the oil to flow, and makes uniform and sufficient coating difficult.

On the other hand, in the lubrication using the fourth solid material, the lubricant can be supplied to the rolling rolls relatively easily and reliably, but it is necessary to install a lubricant pressure supply device in the rolling mill. The universal rolling mill is difficult to install.

Further, it is necessary to supply a particularly large amount of the lubricant to the portion where seizure flaws are likely to occur. However, in the case of a deformed material such as H-section steel, when a large amount of lubricant is supplied, excess lubricant is likely to accumulate on the material due to its shape and posture during rolling. When the lubricant is solid, if it accumulates on the material, the surplus lubricant pushes the surface of the product to cause flaws. Therefore, the supply amount of the lubricant is limited, and insufficient lubrication may occur in a portion where seizure defects are likely to occur.

An object of the present invention is to provide a lubrication method in hot rolling in which the lubricant can be easily supplied, the lubrication effect is high, and there is no concern about the occurrence of indentation flaws due to the surplus lubricant.

[0009]

The method of lubrication in hot rolling according to the present invention comprises 10 to 60% by weight of one or two of graphite and mica on the surface of the material on the inlet side of the hot rolling mill.
It consists of water glass containing 10 to 50% by weight of anhydrous sodium silicate, and has a viscosity of 200 to 5000 c.
It is characterized in that a lubricant adjusted to p is applied, and the excess lubricant accumulated on the surface of the material is removed by air, and the material is passed through a hot rolling mill.

[0010]

The lubricant used in the lubrication method of the present invention is a fluid in which a solid lubricant main agent is mixed with water glass, and does not pop off even when applied to a heated material to be rolled and adheres to the material. Good nature. In addition, a solid lubricant base agent ensures sufficient lubricity, and spray coating is also possible.

In the lubrication method of the present invention, since the present lubricant is applied to the material surface at the entrance side of the hot rolling mill, the lubricant can be easily supplied without being restricted by the equipment of the hot rolling mill. It can be carried out. The lubricant applied to the material surface adheres well to the surface and is not affected by roll cooling water or the like. When a large amount of lubricant is supplied, excess lubricant accumulates on the surface of the material, but since this is removed by air, there is no concern about indentation flaws. Therefore, a large amount of lubricant can be supplied.

This lubricant uses one or two of graphite and mica as its main component. The content of 10 to 60% by weight means that if less than 10% by weight, seizure occurs,
This is because if it exceeds 60% by weight, the dispersion stability of the main agent is impaired and the spray coating operation due to gelation (increased viscosity) becomes difficult.

Anhydrous sodium silicate is a binder for adhering the lubricant main agent to the material to be rolled. The aqueous solution of sodium silicate is called water glass. The lubricant is a mixture of water glass and a main lubricant. The content of the anhydrous sodium silicate is 10 to 50% by weight,
This is because if it is less than 0% by weight, the necessary adhesiveness cannot be obtained because it does not function as a binder, and if it exceeds 50% by weight, gelation (increased viscosity) occurs and the spray coating operation becomes difficult.

In the present lubricant, its viscosity is determined by the viscosity of water glass used and the amount of water added thereto, and the viscosity of water glass is determined by the amount of water contained in the water glass. Therefore, increasing the viscosity means decreasing the amount of water contained in the lubricant, and decreasing the viscosity means increasing the amount of this water. When the viscosity is less than 200 cp, when the lubricant is applied to the heated high temperature rolled material, the water in the lubricant explosively vaporizes and the lubricant is scattered, so that the surface of the rolled material is not covered with the lubricant. Not attached sufficiently. If the viscosity exceeds 5000 cp, gelation (increased viscosity) occurs, making spray application impossible. Therefore, the viscosity is 200 to 5000 cp, which corresponds to about 30 to 70% by weight in terms of water content.

Appropriate timing of applying the present lubricant is 1 to 60 seconds before the start of rolling.

The lubrication method of the present invention is intended for hot rolling in general, but is particularly suitable for hot die rolling of shaped steel, steel sheet pile and the like because the material shape is complicated and the lubricant easily accumulates on the material. When the hot rolling is, for example, rolling of H-section steel, when the lubricant is excessively supplied, the surplus lubricant is accumulated on the web sandwiched between the flanges on both sides of the material. Since the lubricant contains a solid main lubricant, if excessive lubricant is left unattended, indentation defects occur. However, in the lubrication method of the present invention, since the excess lubricant accumulated on the material is removed by air,
There is no risk of indentation. Therefore, it becomes possible to excessively supply the lubricant. Therefore, a sufficient amount of lubricant can be supplied to the portion where seizure flaws are likely to occur.

[0017]

EXAMPLES Examples of the present invention will be described below.

The effectiveness of the present invention was investigated by the rolling-sliding friction tester shown in FIG. 2, which is assumed to be a hot rolling mill. 6 is a material roll corresponding to the material to be rolled, 7 is a tool roll corresponding to a rolling roll, 8 is a high frequency heating coil for heating the material roll 6, 9 is a spray nozzle for applying a lubricant, and 10 is a surplus of lubricant. This is an air nozzle used for exclusion.

In the friction test, the material roll 6 was rotated and heated to the test temperature by the high-frequency heating coil 8. Next, the lubricant was sprayed onto the outer peripheral surface of the material roll 6 by the spray nozzle 9. And the air nozzle 9
The tool roll 7 was brought into rolling contact with the material roll 6 while removing the excess lubricant by the air jetted from. After the test, the outer peripheral surface of the material roll 6 was observed, the lubricity was evaluated from the state of the surface skin, and the occurrence of indentation flaws was investigated.

SUS304 heated to 1000 ° C.
A lubricant was sprayed on the surface of the steel sheet from a distance of 50 mm by air spraying, and the sprayability and adhesion were investigated.

Table 1 shows the material and dimensions of the material roll and the tool roll, and the friction test conditions. Table 2 shows the composition and performance of the lubricant used. In Table 2, ◯ means good, Δ means good, and x means bad.

[0022]

[Table 1]

[0023]

[Table 2]

No. 1 containing 10 to 60% by weight of graphite and / or mica, 10 to 50% by weight of anhydrous sodium silicate, and having a viscosity adjusted to 200 to 5000 cp.
The lubricant of No. 5 has good sprayability and adhesion, and has good seizure resistance. However, if excessive lubricant is not removed from the material surface, indentation flaws will occur. On the other hand, in the examples of the present invention, the lubricants Nos. 1 to 5 are used and the lubricant is removed by air, so that excellent lubricity is ensured and indentation flaws are prevented.

[0025]

As is apparent from the above description, in the lubrication method in hot rolling of the present invention, the lubricant is applied to the material surface by spraying or the like on the inlet side of the hot rolling mill. It is extremely easy and does not require any equipment changes to the rolling mill. In addition, the adhesiveness of the lubricant is good, the lubricity is not deteriorated by the roll cooling water, and an oil separation / collection device or the like is not required. Then, by removing the surplus lubricant, a large amount of lubricant can be supplied. Therefore, sufficient lubrication can be easily performed even in hot-type rolling of profile steels, steel sheet piles, and other profile materials that are difficult to lubricate due to severe processing.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of hot die rolling of H-section steel.

FIG. 2 is an elevation view (A) and a plan view (B) showing a schematic configuration of a friction tester.

[Explanation of symbols]

 1 Material 2, 3 Pore Roll 4 Vertical Roll 5 Horizontal Roll 6 Material Roll 7 Tool Roll 9 Spray Nozzle 10 Air Nozzle

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Claims (1)

[Claims] 1. A water glass containing 10 to 60% by weight of graphite and one or two kinds of mica and 10 to 50% by weight of anhydrous sodium silicate on the surface of the material on the inlet side of the hot rolling mill. And applying a lubricant whose viscosity is adjusted to 200 to 5000 cp, and passing the material through a hot rolling mill while removing excess lubricant accumulated on the surface of the material by air. Lubrication method in hot rolling.